Ah, open mic. My first ever gig was an open mic night, at the Inn on The Prom in Worthing. They asked us back and did 6 weeks running. That was about 25 years ago though.
Saw many a decent act in there, and a few shoddy ones. Limehouse Lizzy were/are the best tribute act I've ever seen (I don't normally do tribute acts), they played there a few times. Saw lots of local acts too, did 'From the Jam' originate locally? SusSex Pistols were not so good, but now it's long time closed, part of the next door hotel now.
I seem to remember being asked to "play quietly" so we ddn't disturb the hotel residents upsairs. Not too easy for a 5 piece band to play quietly !